This disclosure is directed to a method for treating a biobased feedstock generated as a co-product in fermentation-derived renewable fuel and distilled spirit production processes that utilize grain-based crops. The processing of the biobased feedstock by solvent extraction results in a composition that is well suited for subsequent melt processing with a polymer matrix.
The production of fermentation-derived renewable fuels or distilled spirits from grain-based agricultural materials often creates co-products that are generally sold as feed or burned or gasified for use as an energy source. The co-products are characterized as biobased feedstocks that result from the fermentation of grains. There have been various attempts to recover and refine such biobased feedstocks for uses that generate a greater value for the feedstock on a per pound basis. For example, distillers dried grains with solubles (“DDGS”) have been placed in various plastics as fillers. However, such applications can be problematic with respect to achieving acceptable physical characteristics in the resulting composite materials.
One particular biobased feedstock is derived by distilling fermented grain-based material to produce a distillate fraction (such as ethanol or butanol) and a bottoms fraction, which is often referred to as whole stillage. The whole stillage is comprised of water and all of the parts of the fermented grain-based material that were not recovered in the distillate fraction. For corn-based ethanol processes, the whole stillage may comprise non-fermented starch and other carbohydrates, hemicellulose, corn hull, corn protein, corn fiber, corn oil, and ash. The whole stillage is typically subjected to a press or centrifugation process to separate the coarse solids from the liquid. The liquid fraction is commonly referred to as distillers solubles or thin stillage. Thin stillage is frequently concentrated in an evaporator to become condensed distillers solubles, often referred to as “CDS”, which is also commonly referred to as syrup. The coarse solids, or wet cake, collected from the centrifuge or press are known as wet distillers grains. Drying the wet distillers grains produces dried distillers grains or “DDG.” The wet distillers grains can be combined with the CDS to form what is commonly referred to as wet distillers grains with solubles, which can then be dried to form DDGS compounds. The industry continues to seek opportunities to place such materials in higher value products and applications.